I think my Center Channel may have gone dead.

When my receiver is in any of the advanced modes such as Dolby, TXH, ProLogic, etc... There is NO voice. Modes such as Pure Audio and Direct work fine, but I can't tell if the voice is coming out of the Center or Tower Speakers.

I bought my system back in September. Would that item still be covered under warranty? How do I determine if it is my Axiom or possibly my Onkyo receiver?

Any info would be greatly appreciated.

Thanks